The objective of the proposed research is to evaluate possible mechanisms of autoantibody formation in rheumatoid arthritis and systemic lupus erythematosus (SLE). More specifically, the possible role of helper and suppressor T lymphocyte functions in autoantibody formation will be examined. The possible presence of enhancing factors for the synthesis of Ig and rheumatoid factors will be investigated in rheumatoid synovial fluid and incubates of rheumatoid synovial tissue. Ig synthesis will be measured by the radioactive immune coprecipitation technique. The possible role of lysosomal proteases in rheumatoid synovial effusions in activating B cells to synthesize Ig and rheumatoid factor will also be examined. In addition, the action of aggregated IgG on the synthesis of Ig and rheumatoid factor by circulating peripheral blood leukocytes of mitogens, DNA and polynucleotides on Ig and anti-DNA synthesis will be investigated. Anti-DNA formation will be measured by a plaque-forming technique using PBL. Similar experiments will be carried out using spleen cell suspensions from NZB/NZW FI hybrid mice. It is hoped in this way to elucidate the mechanism whereby increased Ig, rheumatoid factor and anti-DNA synthesis occur in rheumatoid arthritis and SLE.